Field
The described technology generally relates to a pixel circuit and an organic light-emitting diode (OLED) display including the same.
Description of the Related Technology
A basic OLED display pixel circuit includes an OLED and a driving transistor. The driving transistor controls the amount of a current to be supplied to the OLED according to a voltage difference between a gate and a source of the driving transistor. The circuit also includes a switching transistor to transmit a data voltage to the driving transistor to control luminance of the OLED. The circuit further includes a storage capacitor connected to the driving transistor to maintain the luminance of the OLED during a frame and to maintain a voltage between the gate and the source of the driving transistor.
In order to display a more vivid image, the resolution of the OLED display circuit increase, and the size of each pixel must decrease. In order to reduce the size of the pixel, the storage capacitor must be made smaller.
When a voltage level of a gate signal to control a transistor of the pixel is changed, a gate voltage of the driving transistor can inadvertently change. As a result, the luminance of the OLED may change during the frame. Moreover, a parasitic capacitance between a channel and a gate of the transistor may change according to degradation of the transistor with usage. Thus, it is difficult to compensate for a change of the gate voltage of the driving transistor when a variable amount gate voltage changes proportionally to a change of the voltage level of the gate signal.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it can contain information that does not constitute the prior art that is already known in this country to a person of ordinary skill in the art.